1. Field of the Invention
A chain tool used to break or assemble a chain includes an adjustable element that enables its use on chain of various different widths. Chain tools have existed and are in widespread use however there is a chain and tool compatibility situation that limits the use of most chain tools to a narrow range of chain widths if chain pin driving accuracy is required.
2. Summary of the Invention
A chain tool of the general type disclosed here is a tool that is used in working with chain used as a drive or indexing mechanism in industrial applications. Common uses of chain of the type pertinent to this invention include chain used in a motor/axle drive system having a drive sprocket and a driven sprocket, for instance in a go-kart, or, as another example, in a bicycle drive system. A chain tool is used to separate semi-permanently connected chain links so that a chain can be shortened, lengthened, or separated and reassembled to fit over, for instance, a drive sprocket and a driven sprocket.
A chain is made up of links having several parts. Each link includes a first and a second outboard plate of a generally elongated shape with an aperture at each end of the plates passing through the plates. First and second inner plates separated by and fixedly mounted to, a pair of bushings, one at each end of the first and second inner plates. These chain link elements are assembled as a unified structure and are not designed to be taken apart. The inner chain link elements make up a portion of the chain link located between the first and the second outboard plates. The bushings of the chain link elements between the inner plates may be, in certain types of chain, provided with a free-floating sleeve carried on the bushings of the inner plates. The free-floating sleeves function as bearing surfaces that interface with the sprockets that the chain is directed around. The chain tool presented here will work equally well with chain having bushings only or with chain having sleeves over the bushings.
Pins are used to connect a link set together and to connect one link set to another link set. A pin will pass through an aperture in a first outboard plate, through the bushing of the inner plates and out through an aperture of the second outboard plate. This, plus the inclusion of a second pin will, for the purposes of this specification will be the components making up a chain link.
The second pin is used to connect one chain link to a second chain link. The second chain link will have outer plates at one end thereof and a second end that just has the inner link. The outer plate end of the link to be attached to the first link will be positioned over the inner link portion of the first link and a pin will be forced through the first outer plate of the second chain link, through the bushing of the first link and finally into and through the aperture of the second outboard link of the second link. This is a very simple system that has been used on chain for many years and will therefore be familiar and routine to a person of ordinary skill in the chain art.
In order to allow the connection of one chain link to another it is necessary to be able to push the chain link pin inboard through the outer plate, through the inner link portion and out through the second outer plate accurately and consistently. To remove a link from a chain it is necessary to push the aforesaid pin out of the outboard plate, through the inner link portion and ideally only partially out the second outboard plate—so that the pin is retained in the second outboard plate for future use and to make it easier to push the pin back in place on a subsequent attachment.
The tool to do this is a chain tool, often called a “chain breaker,” that is commonly used to separate and reconnect links of chain. A chain tool usually is compatible with only a single width of chain or if it can accommodate various chains of different widths it may be a less precise universal chain tool that does not have the accuracy necessary for assembling high performance chain and its links as may be found on performance go-karts for instance. In such applications it is imperative that the chain be properly assembled as the chain is being used to drive a go-kart that could be traveling over a hundred miles an hour.
The chain tool presented here differs from the chain tools known to the inventor in that the forces required to push a link pin in or out of a chain link are restrained by a substantial wall surface that is on the side of the chain link that is away from the side where the chain pin is being pushed. This allows the significant forces needed to resist the pin displacement forces to be resisted in a way that prevents distortion of the “near side” outer chain plate as is possible with known chain tools.
As chain is available in different widths it is important that the width of the chain is accommodated by the chain tool without compromising the precision and functionality of the tool. Current chain tools may accommodate different widths of chain but to do so cannot provide the secure support needed to hold a chain securely to avoid chain distortion. The adjustability of the inventor's chain tool, provided by the use of a main spacer and shims or secondary spacers does provide for the ability of the chain tool to accommodate chain of different widths while providing the solid anvil needed to assure that the chain links, normally the chain plates, are not distorted as the chain is being assembled or “broken.”
Thus it is an object of this invention to provide a chain tool for adding chain links, subtracting chain links or otherwise simply connecting chain links, that is adjustable to accommodate chain of different widths.
It is also an object of this invention to provide adjustability to a chain tool by the use of spacers, including a main spacer and secondary spacers or shims.
An advantage of this chain tool is that it provides for support of a chain link by positioning an offside chain plate against a secure wall surface, acting as an anvil surface, while chain pin removal or replacement is being accomplished through a chain plate on the other side of the chain link.
One more advantage is that the chain tool is provided with recesses to accommodate chain pin ends on the offside of the chain links being services such that the associated chain plates can rest flat and securely against a support wall of the chain tool.
Another object of the invention is to allow a chain link to contact one or more of a series of upstanding pickets that provide an anvil surface for the inboard surface of outer chain links.
It is also an object and advantage of the invention to provide a first anvil surface for contacting the inside surface of a chain plate and a second anvil surface for contacting the outboard surface of an offside chain plate when a chain link is placed in the chain tool.
Another object of the invention is to provide for chain tool adjustment so that the first and second anvil surfaces correspond with the distance between the inner surface of a first chain plate and the outer surface of an offside chain plate.
It is also an advantage of the invention that virtually all the components of the chain tool can be replaced with spare parts without the need to scrap the entire tool. For instance, the alignment plate, the main spacer, the end plate, the rod and the secondary spacers are all easily substituted with replacement parts by a person of ordinary skill in the art.
These and other advantages of the invention will be discernable from the following description of the invention.
The preferred embodiment of the invention is described in the following Detailed Description of the Invention and attached Figures. Unless specifically noted, it is intended that the words and phrases in the specification and claims be given the ordinary and accustomed meaning to those of ordinary skill in the applicable art or arts. If any other meaning is intended, the specification will specifically state that a special meaning is being applied to a word or phrase. Likewise, the use of the words “function” or “means” in the Detailed Description is not intended to indicate a desire to invoke the special provisions of 35 U.S.C. Section 112, paragraph 6 to define the invention. To the contrary, if the provisions of 35 U.S.C. Section 112, paragraph 6, are sought to be invoked to define the inventions, the claims will specifically state the phrases “means for” or “step for” and a function, without also reciting in such phrases any structure, material, or act in support of the function. Even when the claims recite a “means for” or “step for” performing a function, if they also recite any structure, material or acts in support of that means of step, then the intention is not to invoke the provisions of 35 U.S.C. Section 112, paragraph 6. Moreover, even if the provisions of 35 U.S.C. Section 112, paragraph 6, are invoked to define the inventions, it is intended that the inventions not be limited only to the specific structure, material or acts that are described in the preferred embodiments, but in addition, include any and all structures, materials or acts that perform the claimed function, along with any and all known or later-developed equivalent structures, materials or acts for performing the claimed function.